[PATCH 17/39] scsi: explicitly release bidi buffers

Christoph Hellwig
2014-03-17T13:27:50Z

[-- Attachment #1: 0017-scsi-explicitly-release-bidi-buffers.patch --]
[-- Type: text/plain, Size: 3432 bytes --]

Instead of trying to guess when we have a BIDI buffer in scsi_release_buffers
add a function to explicitly free the BIDI ressoures in the one place that
handles them. This avoids needing a special __scsi_release_buffers for the
case where we already have freed the request as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/scsi_lib.c | 47 ++++++++++++++++++++---------------------------
1 file changed, 20 insertions(+), 27 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index debe30a..3012700 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -511,8 +511,6 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
scsi_run_queue(sdev->request_queue);
}

-static void __scsi_release_buffers(struct scsi_cmnd *, int);
-
/*
* Function: scsi_end_request()
*
@@ -568,7 +566,7 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
* This will goose the queue request function at the end, so we don't
* need to worry about launching another command.
*/
- __scsi_release_buffers(cmd, 0);
+ scsi_release_buffers(cmd);
scsi_next_command(cmd);
return NULL;
}
@@ -624,30 +622,10 @@ static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
}

-static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
-{
-
- if (cmd->sdb.table.nents)
- scsi_free_sgtable(&cmd->sdb);
-
- memset(&cmd->sdb, 0, sizeof(cmd->sdb));
-
- if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
- struct scsi_data_buffer *bidi_sdb =
- cmd->request->next_rq->special;
- scsi_free_sgtable(bidi_sdb);
- kmem_cache_free(scsi_sdb_cache, bidi_sdb);
- cmd->request->next_rq->special = NULL;
- }
-
- if (scsi_prot_sg_count(cmd))
- scsi_free_sgtable(cmd->prot_sdb);
-}
-
/*
* Function: scsi_release_buffers()
*
- * Purpose: Completion processing for block device I/O requests.
+ * Purpose: Free resources allocate for a scsi_command.
*
* Arguments: cmd - command that we are bailing.
*
@@ -658,15 +636,29 @@ static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
* Notes: In the event that an upper level driver rejects a
* command, we must release resources allocated during
* the __init_io() function. Primarily this would involve
- * the scatter-gather table, and potentially any bounce
- * buffers.
+ * the scatter-gather table.
*/
void scsi_release_buffers(struct scsi_cmnd *cmd)
{
- __scsi_release_buffers(cmd, 1);
+ if (cmd->sdb.table.nents)
+ scsi_free_sgtable(&cmd->sdb);
+
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+
+ if (scsi_prot_sg_count(cmd))
+ scsi_free_sgtable(cmd->prot_sdb);
}
EXPORT_SYMBOL(scsi_release_buffers);

+static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
+{
+ struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
+
+ scsi_free_sgtable(bidi_sdb);
+ kmem_cache_free(scsi_sdb_cache, bidi_sdb);
+ cmd->request->next_rq->special = NULL;
+}
+
/**
* __scsi_error_from_host_byte - translate SCSI error code into errno
* @cmd: SCSI command (unused)
@@ -799,6 +791,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
req->next_rq->resid_len = scsi_in(cmd)->resid;

scsi_release_buffers(cmd);
+ scsi_release_bidi_buffers(cmd);
blk_end_request_all(req, 0);

scsi_next_command(cmd);
--
1.7.10.4